Precise fluid-dividing apparatus

ABSTRACT

Apparatus for the precise division of a flowing fluid into plural portions of selected relative volumes employs one or more stream splitters, each of which has a single input conduit feeding into a chamber from which (n) output conduits feed outwardly, for effecting a one-to-n split simultaneously. The stream splitter chamber has minimal volume. Further, a conical fluid-dispersion element is in the stream splitter chamber pointed at the input conduit. Where the input fluid is to be divided into a significant number of output portions, minimal overall chamber volume is achieved by using two or more successive stages of stream splitters.

United States Patent [191 Hurtig et al.

PRECISE FLUID-DIVIDING APPARATUS Inventors: Carl llur'tig, Scituate; Robert L.

Kent, Andover; Leo J. Blumle, Milton, all of Mass.

Damon Corporation, Needham Heights, Mass.

Filed: Oct. 22, 1971 Appl. No.: 191,611

Assignee:

References Cited UNITED STATES PATENTS 7/1943 MacDougall l37/599 X 3/1966 Callahan, Jr. et al 137/608 4/1969 Smythe 73/423 A [451 Nov. 19, 1974 3,489,525 l/l970 Nazelson 73/423 A 3,536,45l 10/1970 Ludwin..; 137/567 X 3,643,689 2/1972 lsreeli l37/56l A Primary ExaminerWilliam R. Cline Assistant Examiner-Ira S. Lazarus Attorney, Agent, or Firml(enway & Jenney ABSTRACT Apparatus for the precise division of a flowing fluid into plural portions of-selected relative volumes employs one or more stream splitters, each of which has a single input conduit feeding into a chamber from which (n) output conduits feed outwardly, for effecting a one-to-n split simultaneously. The stream splitter chamber has minimal volume. Further, a conical fluiddispersion element is in the stream splitter chamber pointed at the input conduit. Where the input fluid is to be divided into a significant number of output portions, minimal overall chamber volume is achieved by using two or more successive stages of stream splitters.

8 Claims, 5 Drawing Figures PATENTEL 9119574 3.848.633

, sum 10? 2 AMPLER m f-IO L PROPORTIONING PUMP l6 HVHHHHHHHHHHi TO ANALYSIS INSTRUMENT \I4 FIG. i

PEG. 2

PRECISE FLUID-DIVIDING APPARATUS BACKGROUND This invention relates to apparatus for splitting a flowing fluid with high precision into plural portions of selected relative volumes. The invention is particularly suited for splitting a sample of blood serum or other biological fluid into plural portions, which are then separately delivered to ana analysis instrument for the measurement of different constituents in the original sample liquid. Accordingly, for clarity of description, the invention is described with principal reference to such an application; however,.features of the invention are not limited in this manner, but rather are useful with other equipments.

Sample liquid that is to be subjected to multiple constituent-determining analyses often is not homogeneous. For example, the addition of a diluent, or a preservative, to the original biological liquid without complete mixing often results in an inhomogeneous sample liquid. When such an inhomogeneous liquid is divided into multiple portions by feeding'it along a conduit that branches to form the portions, the volumes of sample material in the several portions can differ significantly. For example, where blood serum diluted twenty times is split into numerous identical branch conduits before complete mixing with the diluent, improper splitting can result in one portion having one-half or even less serum than is present in another portion of equal volume.

Discrepancies of this nature between the serum con centrations in supposedly identical sample aliquots delivered to an analysis instrument will result in highly inaccurate analysis results.

Moreover, stream splitting errors of the foregoing na- 4 ture cannot be corrected by compensation. This is because the errors do not repeat identically on successive sample liquids.

Accordingly, it is an object of this invention to provide apparatus for splitting each of a succession of inhomogeneous fluid segments with precision into several portions of selected relative volumes.

Another object of the invention is to provide splitting apparatus of the above character which is of the smallest inhomogeneity that is to be divided with precision. This construction is provided in order that even a small inhomogeneity in the incoming fluid segment fills the chamber. The small inhomogeneity then splits to the output conduits with essentially the same precision as a homogeneous unit of fluid. As a result, all fluid segments fed to the splitter divide essentially identically. I

Further, the chamber of the stream splitter. provides fluid paths of equal fluidic resistance-from the input conduit to the output conduits. This feature also increases the precision with which fluid segments are split; because it ensures that the leading edge of each fluid segment, and of each inhomogeneity therein, arrives at the several output conduits simultaneously.

The invention is preferably practiced with a stream splitter having a vertical, cylindrical, input conduit feeding intoa splitting chamberhaving a cylindrical outer wall with the cylinder axis thereof coincidentv with the input conduit axis. The output conduits feed from the splitter chamber at the cylindrical outer wall and at uniform angles relative to the vertical.

Further, the invention provides a solid conical element in the chamber oriented with the cone axis coincident with the axis of the cylindrical chamber wall and with the cone taper pointing toward the input conduit. The cone apex preferably is closely adjacent the juncture of the input conduit into the chamber. The base of the cone can merge directly into the cylindrical outer wall of the chamber, i.e., the base of the cone preferably has a diameter equal to the diameter of the cylindrical outer wall of the chamber. Thus, a preferred stream splitter chamber provided by the invention is a solid of revolution traced by revolving a triangle about the vertical axis of the input conduit; the triangle being oriented with one side parallel to this axis and with the corner opposite that side lying along the axis. Further,

' however, the taper of the cone can be rounded, usually branching conduit type; that is, in which a single conduit carries the successive fluid segments to be split and branches into numerous output conduits, each of which receives a selected portion of the initial fluid segment.

A further object of the invention is to provide splitting apparatus of the above character which can be fabricated at relatively low cost.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

SUMMARY OF THE INVENTION concavely as in a horn shape, rather than straight.

The conical, flaring inner wall which the invention provides in the stream splitter chamber is considered to provide at least two advantages, both of hich contribute to the precision with which the stream splitter operates. One advantage is that the tapering conical body significantly reduces the chamber volume theoretically by one-third for a straight-sided cone relative to the volume. of a chamber having a cylindrical volume, i.e. without an inner cone. The other advantage attributed to the cone is that, with the cone apex centered in the stream of incoming fluid, this apex together with the sidewalls of the cone provided a symmetrical and uniform diversion of the input fluid to the several output conduits.

A stream splitter embodying the invention also transfers fluid from the input conduit to the output conduits without either gravitational or structural preference of fluid for one output conduit over another. The stream splitter geometry noted above-that of having a vertical input conduit centered relative to the chamber cylindrical outer wall and with uniformly-spaced and equally-inclined output conduits-is considered preferable to satisfy this aspect of the invention.

A further characteristic of the stream splitter embodying the invention is that the largest area of the chamber in a horizontal plane, assuming a verticallyoriented input conduit, is preferably substantially equal to, and at least of the same order of magnitude as, the

sum of all the cross sectional areas of the output conduits of the chamber. This construction is considered desirable to allow fluid to flow through the stream splitter with relatively uniform velocity and hence with minimal pressure differential across the chamber.

The foregoing features which the invention provides for a branching-conduit type stream splitter can be employed in stream splitters of any number of output conduits. However, further in accordance with the invention, the stream splitter constructed in this manner preferably has no more than six or eight output conduits. This is because it has now further been found that successive stages of stream splitters, each generally having no more than six or eight output conduits, can split successive non-homogeneous fluid segments with greater precision than a single stream splitter having the desired number of total output conduits. An important reason for using two or more successive stages of stream splitters in this manner is that a multiple-stage stream splitter system can attain a smaller total chamber volume, computed as the sum of the chamber volumes of all the stream splitters in the system, than a single stream splitter providing the same overall division. The attainment of small overall stream splitter chamber volume is a significant factor in attaining precise splitting of flowing fluid segments according to the invention.

A further feature of a multiple-stage stream splitter system according to the invention is that the fluid portions progress through the several stages in phase with each other.

Moreover, where liquid portions of different volumes are required from a single liquid segment, a stream splitter or system of stream splitters can be constructed in the foregoing manner with identically-sized output conduits. The desired different output portion volumes are obtained by pumping liquid from the different output conduits at different rates to yield the desired different portion volumes. This arrangement generally is far more economical than providing different-sized output conduits on the splitters themselves.

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts exemplified in the constructions hereinafter set forth, and the scope of the invention is indicated in the claims.

BRIEF DESCRIPTION OF FIGURES For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of apparatus for delivering liquid portions of selected relative volumes to analysis equipment and employing stream splitter apparatus embodying features of the invention;

FIG. 2 is a perspective view, partly broken away, of a four-way stream splitter embodying features of the invention;

FIG. 3 is a plan view of the stream splitter of FIG. 2;

FIG. 4 is an elevation view, partly broken away, of the stream splitter of FIG. 2; and

FIG. 5 is a top plan view of a six-way stream splitter according to the invention.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS FIG. 1 shows a stream splitter system 10 that receives fluid segments, having varying degrees of inhomogeneity, in succession from a sampler 12, and delivers portions of selected relative volumes of each segment to an analysis instrument 14 by way of a proportioning pump 16.

The sampler 12 can, by way of illustration, be constructed in the manner disclosed in the commonlyassigned US. Pat. application Ser. No. 105,803 filed .Ian. 12, 1971, in the names of John D. Bannister, .lo-

seph C. Peters and Michael Jordan for Liquids Sampler With Probe-Bathing Chamber." With such a sampler, each segment consists of metered volumes of serum to be analyzed and diluent, and air separates successive segments. Where desired, a mixer can be provided in the fluid path between the sampler and the stream splitter system 10. The pump 16 is typically of the peristaltic type, and the analysis instrument can be constructed in the manner disclosed in the commonlyassigned US. Pat. application Ser. No. 105,805, filed .Ian. 12, 1971 in the names of David I. Kosowsky, Andres Ferrari and Carl R. I-Iurtig for Constituents- Measuring Chemical Analyzer Having Multiple Concurrently-Operated Aliquot-Processing Conveyors."

The illustrated stream splitter system 10 divides each liquid segment received from the sampler 12 into 24 portions. The system has an input conduit 18 feeding from the sampler to a first splitter stage having a six-way splitter 20 that divides each liquid segment into a set of six output portions. Intermediate conduits 22 feed these output portions to a second splitter stage 10b that illustratively has three six-way splitters 24, 26 and 28, and one four-way splitter 30. In addition, output conduits 34, feed two portions from the first stage splitter 20 directly to the pump tubes 36 that lead to the peristaltic pump 16.

Output conduits 38 deliver the several liquid portions from the second stage splitters 24, 26, 28 and 30 to other pump tubes 36.

The stream splitter system 10 is further arranged to feed liquid portions through it in the different conduits essentially in phase. Accordingly, the lengths of the intermediate conduits 22 are selected to deliver liquid portions from the splitter 20 to the splitters 24, 26, 28 and 30 simultaneously. The output conduits 38 are similarly tailored in length to deliver all output portions to the pump tubes 36 simultaneously. Further, the two conduits 34 are of such lengths that the liquid portions therein arrive at the pump tubes 36 coincident with the liquid portions from the second stage splitters.

The reason for providing this in-phase operation is to have any time-varying action of the proportioning pump 16 act on the fluids in all the stream splitters in an identical manner. This in turn avoids differential splitting in different splitters due to variations in the pump action, and thereby contributes to attaining precise splitting of successive segments.

In a first example of the stream splitting system 10, each pump tube 36 fed by an output conduit 34 has a cross-sectional area (a Further each tube 36 fed by an output conduit 38 from four-way splitter 30 has a cross-sectional area of (a /4). Each remaining pump tube 38 has a cross-sectional area of (a,/6). Accord- 5, ingly, from each liquid segment of volume (v,) from sampler 12, the pump 16 draws aliquots having volume ratios of (v /6), (v /24) and (v /36), respectively, from the foregoing three sets of pump tubes. To provide this operation, the first-stage splitter 20 divides each segment into six equal portions, each of the volume (VI/6). The output conduits 34 deliver two portions of this volume directly to the pump 16 for delivery to the analysis instrument 14. The four-way splitter 30 in the second stage 10b divides the (v,/6) liquid volume which it receives into four equal portions, and delivers four output portions each of volume (v /24) to the pump 16 and hence the analysis instrument 14. Similarly, each sixway splitter 24, 26 and 28 delivers six output portions to the proportional pump and hence the analysis instrument, each with a volume of (v l36).

The stream splitting system 10 can further provide output portions of different volumes from a single splitter having equal-size output conduits leading from the chamber therein. For example,two output conduits 28a from the six-way splitter 28 can feed pump tubes of area (a l4), while the remaining pump tubes have the same sizes as in the foregoing example. In this instance, the pump will draw aliquots from the outputs 280 which are of the same volume as the aliquots it draws from the four-way splitter 30. However, in this instance, the volume ratios of the aliquots are not in the 1:426 ratio as they were in the foregoing example.

In a specific embodiment for providing the latter operation, with approximate numerical values, the pump More particularly, a vertical cylindrical passage 65 (FIG. 4) in the block 54 forms the inner end of the input conduit 42 and forms the outer cylindrical wall 66 of the splitter chamber 44. The outlet conduits extend radially outward from this cylindrical wall 66. The illustrated input conduit 42 continues without significant change in size from the passage 65 to the inlet tubule 56.

The illustrated output conduit 46, typical of the others, has a neck-like passage section 68 that leads out from the cylindrical wall 66. The conduit size increases from the neck section to a coupling passage section 70 having a bore equal or close to the cylindrical passage in the output tubule 58 that extends the output conduit 46 beyond the block 54. As noted, the other output conduits can be of identical construction.

With this construction, the chamber 44 is formed by the section of the inlet conduit passage 65 from which the neck-like passage sections 68 of the outlet conduits feed. Each neck-like passage section illustrated is angled at 90 from the adjacent passage section, and the four sections are centered in a common horizontal plane. Thus the height of chamber 44, along the vertical axis 71 of the input conduit 42, is equal to the diameter of the outlet conduit passage section 68.

This diameter is selected to conform with at least two criteria. One criterion is that the area, in a plane parallel to that of FIG. 3, within the cylindrical outer wall 66 of the chamber is approximately equal to, or at least of I the same order of magnitude as, the sum of the crosstubes 36 connected to the output-conduits from the Finally, the two pump tubes connected tothe stream splitter conduits 34 have a still larger inside diameter of 0.065 inch. With this arrangement of the pump tube inside diameters, and with each liquid segment fed to the stream splitter 20 having a volume of 3,800 microliters, the first stage splitter 20 delivers 600 microliters to the second stage stream splitters 24 and 26, delivers 800 microliters to'the second stage stream splitters 28 and 30,. and delivers 500 microliters to each output conduit 34. The second stage splitters 24 and 26 deliver 100 microliters of liquid to each output conduit 38 and, accordingly, each pump tube 36 which they feed. The aforementioned four output conduits from splitter 28 that feed into 0.030 ID pump tubes also receive 100microliters of the initial liquid segment. However, each of the other two output conduits 28a from the, six-way splitter 28 and of the output conduits from the fourway splitter 30 receives 200 microliters of liquid.

FIGS. 2, 3 and 4 show'a construction according to 60, 62 and 64, to provide these parts of the stream splitter. The chamber 44 and the conduits, and hence the conduit-forming passages, preferably are of circular cross section, as illustrated.

sectional areas of the outlet conduits that feed from this surface 66, i.e., of the neck-like passage sections 68. Withthis so-called equal-area" construction, liquid flows'from the inlet conduit to the several outlet conduits with a substantially uniform velocity, and there are minimal pressure differentials across the splitter chamber.

The other criterion is that each outlet conduit intersects the chamber entirely along the cylindrical outer wall of the chamber, as opposed to intersecting an adjacent outlet conduit. This objective ensures that there is a narrow but finite portion of the cylindrical wall 66 between the entry of adjacent outlet conduits into the chamber. Thus, by way of example, a small segment 72 of the chamber outer wall 66 is between the entry of adjacent outlet conduits 46 and 52 into the chamber 44. An approximate quantitative expression for satisfying the second criterion is that the circumference of the chamber cylindrical surface 66 be slightly greater than the sum of the diameters of the outlet conduits that leads from the chamber.

Further in accordance with the invention, the stream splitter 30 has a cone 74 within the chamber 44 and protruding toward the input conduit 42. The cone, illustrated as a straight-sided right circular cone, is concentric with the passage 65 and is oriented with the cone apex pointed toward the inlet conduit 42. The illustrated cone 74 shows a further preferred construction in that the cone height is essentially equal to the diameter of the neck-like passage sections 68 of the outlet conduits, and the cone is centered in the chamber 44 so that the apex is at the juncture of the inlet conduit 42 with the chamber. Further, the cone base coincides with the chamber outer cylindrical wall 66, i.e., the diameter of the cone base is equal to the diameter of the chamber wall 66.

The provision of the cone 74 in the splitter chamber reduces the chamber volume by a factor of approximately one-third compared to the volume which the cylindrical wall 66 bounds, i.e., without the cone. Further, the tapered conical surface of the cone provides a fluid diverting surface opposite the inlet conduit 42 and which is considered to enhance the precision with which fluid entering the chamber 44 splits into the several outlet conduits. The tapered surface of the cone also guides fluid from the inlet conduit 42 to the outlet conduits with significantly less turbulent flow than would occur without the cone in the chamber.

The foregoing stream splitter construction will be seen to be highly symmetrical about the input conduit and chamber axis 71. With this construction, there is no structural preference for fluid entering in the inlet conduit to divert to one outlet conduit rather than another. Further, with a vertically-oriented inlet conduit and with outlet conduits at precisely uniform angles relative to the axis 71, there is no gravitational preference for fluid to flow from the inlet conduit into any one outlet conduit rather than another.

With further reference to FIGS. 2, 3 and 4, in the illustrated construction of the four-way splitter 30, the cone 74 is at the end of a stem 76 protruding upward, in a mating bore in block 54, from a disk 78 that is disposed along an outer surface of the block 54. The stem 76 increases in thickness, as shown, in leading from the cone 74 to the disk 78.

By way of example, a four-way splitter as shown in FIGS. 2, 3 and 4 embodying the invention has a passage 65 of 0.040 inch diameter, and has neck-like outlet conduit passage sections 68 of 0.020 inch diameter. The splitter cone 74 has a 90 included angle between the tapered sides, and has a diameter at the base of 0.40 inch, and hence has a height of 0.20 inch.

FIG. 5 shows a plan view of the six-way splitter 24 of FIG. 1. An identical construction can be used for the other six-way splitters 26 and 28 in FIG. 1. The view in FIG. 5 is similar to the FIG. 3 view of the four-way splitter 30. A separate side elevation view of the six-way splitter is not shown, inasmuch as it is identical to the FIG. 4 view of the four-way splitter, except for the additional output conduits on the six-way splitter.

The six-way splitter 24 has a vertical input conduit 82 suitably formed as described with reference to the fourway splitter with a vertical passage of circular cross section from which an input tubule 83 extends outward beyond the splitter-forming block 84. The cylindrical wall of this passage forms the outer wall 86 of the splitting chamber for the six-way splitter.

Six output conduits 88, 90, 92, 94, 96, 98 feed outward from the chamber cylindrical outer wall 86, each with a narrow passage section 100 at its inner end and intersecting the chamber outer wall. The six-way splitter 24 further has a conical element 102 in the splitter chamber opposite and pointed toward the input conduit 82, to diminish the chamber residual volume and to enhance precise splitting of liquid entering the chamber into the six output conduits 88-98.

Fluid splitters in accordance with the invention can have numerous variations from the constructions illustrated. Thus, although a vertical inlet conduit is preferred, this is not necessary, especially where gravitational preferences are not significant. Further, the inlet conduit can feed vertically upward into the splitting chamber, as well as vertically downward as shown.

Further, the splitter can have output conduits of different sizes leading from the splitting chamber. However, it is considered preferable that differently sized conduits be symmetrically arranged relative to the input conduit axis. Thus, by way of example, where a six-way splitter as in FIG. 5 is to have output conduits of different sizes, it is considered preferable to have each pair of diametrically opposite conduits and 96, 88 and 94, and 98 and 92 feed into the chamber wall 86 with essentially equal sizes.

Where the output conduits have different sizes at the chamber outer wall, the conical chamber element is located to divert the leading surface of a fluid segment to enter all the output conduits essentially simultaneously.

With further regard to the cone 74 illustrated in FIGS. 2 and 4, it can alternatively be a conical element having rounded sides, preferably with concave rounding as on a trumpet horn. Further, the cone can have a height different from the chamber height. Then the cone can extend upward from the splitter chamber for a short distance into the input conduit, and alternatively can be shorter than the chamber so that the apex is spaced a short distance within the chamber from the input conduit.

As discussed above with reference to FIG. 1, the use of successive stages of stream splitters to provide an n-way split is preferred in place of a single n-way splitter, where (n) is greater than eight or so, because the former arrangement can yield a smaller total stream splitter volume. In particular, a single, n-way splitter constructed as illustrated hereinabove has a chamber with a volume V, approximately equal to the volume of a cylinder less the volume of a straight-sided circular cone of identical height and base radius as the chamber. Hence the volume is V, 7f: 1r r D (I) where:

r is the radius of the chamber cylindrical outer wall of the n-way splitter, and

D is the diameter of each output conduit leading from that splitter chamber.

Assuming the n-way splitter chamber has a circumference C, equal to the sum of the output conduit diameters, then C 2 1r r n where n is the number of output conduits on the n-way splitter D and r can be expressed as T (n, 1T)

Substituting this value of r, into equation 1 yields 1 "("1 o/ o ("1 o Now consider the total chamber volume V of individual splitters forming a two-stage splitter system as in FIG. I but without the output conduits 34, i.e., with a single first-stage splitter and with four second stage splitters. Where all five splitters have identical chamber dimensions and each has output conduits of diameter D01 V2; 5 7T r2 Do] where:

r is the radius of the chamber cylindrical'outer wall of each of the five splitters. I

Assuming again that each chamber in the two-stage splitter system has a circumference C equal to n5 times the diameter D ,'where n is the number of output conduits on each such splitter,

C =2rrr =n D and Equation can now be written as follows using the value of r of equation 7:

The ratio of the two volumes set forth in equations 4 and 8 is a As a first example, consider a system for dividing a liquid segment into sixteen portions (i.e., n, 16) and having two stages of stream splitters with one splitter in the first stage'and four in the second stage, each of which has four output conduits, i.e., n 4 V71;-

Substituting the square root of n, into equation 9 for n the volumes ratio becomes Thu'sfor-this example, the multiple-stage splitter has a total chamber volume which is less than the chamber volume of a corresponding single splitter by a factor equal to the square root of the number of output portions desired.

1/ 2 ("1) /("1/ l)(m/ 5 64/11, n,/9 2.67

Accordingly, here again the use of the multiple-stage splitter system results in a volume-reduction by a factor involving the total number of output ports desired.

- scription, are efficiently attained. Since certain, changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in alimiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described the invention, what is claimed as new and secured by Letters Patent is:

1. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus comprising A. an input conduit for fluid to be divided,

B. a plurality of. output conduits for receiving said portions of said fluid,

C. means forming a chamber 1. having an outer wall of circular cross section oriented with the center along a vertical axis,

2. having said input conduit feeding thereinto along said vertical axis,

3. having said output conduits feeding out from said outer wall at a common level along said axis, and

4. providing symmetrical fluid passages there through from said input conduit to said output conduits, and D. a conical member disposed in said chamber with the cone axis coincident with said vertical axis, with the apex of said conical member pointed toward said input conduit, and with the conical surface thereof forming at least a portion of the chamber surface spanning said outer wall opposite said input conduit and being located along said axis at the level at which said output conduits feed out from said outer wall.

2. Apparatus as defined in claim 1 in which said conical member has a height along said axis coextensive with the projection along said axis of the junctures of said output conduits with said chamber.

3. Apparatus as defined in claim 2 in which said coni- 1 ca] member has a diameter at the base thereof substantially equal to the diameter of said chamber outer surface.

4. Apparatus as defined in claim 1 in which said conical member has a height along said axis thereof substantially equal to the projection along said cone axis of the opening of at least one output conduit into said chamber.

5. A clinical instrument component for dividing flowing fluid with precision into a number of portions of selected relative volumes, said component having i. a housing having a fluid-dividing chamber therein,

ii. a single input conduit feeding into said chamber,

and iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer side wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis,

B. a separate junction along said side wall for each said output conduit, with said output conduit ii. a single input conduit feeding into said chamber,

and

iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis, B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and C. a conical member i. bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit, and

ii. having the conical surface thereof disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall and intersecting said chamber outer wall to form the entirety of said chamber surface spanning said outer wall opposite said input conduit.

7. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus having i. a housing having a fluid-dividing chamber therein,

ii. a single input conduit feeding into said chamber,

and

iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis,

B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and

C. a conical member bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit and with the conical surface thereof being disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall, the length of said conical member along said vertical axis being coextensive within said chamber with the dimension along said axis of said junctions.

8. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus having i. a housing having a fluid-dividing chamber therein,

ii. a single input conduit feeding into said chamber,

and

iii. a plurality of output conduits feeding out from said chamber,

and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis,

B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and

C. a conical member bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit and with the conical surface thereof being disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall, the length of said conical member along said vertical axis being equal to the dimension of said junctions along said axis.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CQRRECTION PATENTNQ. 3,848,633

DATED 1 November 19, 1974 INV ENTOR(S) Carl R. Hurtig, Robert L. Kent, and Leo J. Blumle It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 42, change "hich" to --which--.

Column 2, line 51, change "provided" to --provide--.

Column 8, correct lines 49, 50 and 51 to read:

where n is the number of output conduits on the n-way splitter-.

Correct the list of references cited by adding the following U.S. Patents cited in the Official Action mailed October 9, 1973:

-- 791,425 5/1905 Johnson 137/262 x 2,059,255 11/1936 Lassiat l37/56l A 2,288,297 6/1942 Naiman l37/56l A Signed and Sealed this twenty-seventh D f January 1976 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ufParents and Trademarks 

1. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus comprising A. an input conduit for fluid to be divided, B. a plurality of output conduits for receiving said portions of said fluid, C. means forming a chamber
 1. having an outer wall of circular cross section oriented with the center along a vertical axis,
 2. having said input conduit feeding thereinto along said vertical axis,
 3. having said output conduits feeding out from said outer wall at a common level along said axis, and
 4. providing symmetrical fluid passages therethrough from said input conduit to said output conduits, and D. a conical member disposed in said chamber with the cone axis coincident with said vertical axis, with the apex of said conical member pointed toward said input conduit, and with the conical surface thereof forming at least a portion of the chamber surface spanning said outer wall opposite said input conduit and being located along said axis at the level at which said output conduits feed out from said outer wall.
 2. having said input conduit feeding thereinto along said vertical axis,
 2. Apparatus as defined in claim 1 in which said conical member has a height along said axis coextensive with the projection along said axis of the junctures of said output conduits with said chamber.
 3. Apparatus as defined in claim 2 in which said conical member has a diameter at the base thereof substantially equal to the diameter of said chamber outer surface.
 3. having said output conduits feeding out from said outer wall at a common level along said axis, and
 4. providing symmetrical fluid passages therethrough from said input conduit to said output conduits, and D. a conical member disposed in said chamber with the cone axis coincident with said vertical axis, with the apex of said conical member pointed toward said input conduit, and with the conical surface thereof forming at least a portion of the chamber surface spanning said outer wall opposite said input conduit and being located along said axis at the level at which said output conduits feed out from said outer wall.
 4. Apparatus as defined in claim 1 in which said conical member has a height along said axis thereof substantially equal to the projection along said cone axis of the opening of at least one output conduit into said chamber.
 5. A clinical instrument component for dividing flowing fluid with precision into a number of portions of selected relative volumes, said component having i. a housing having a fluid-dividing chamber therein, ii. a single input conduit feeding into said chamber, and iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer side wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis, B. a separate junction along said side wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and C. a conical member bounding said chamber side wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit, and with the conical surface thereof being disposed along said vertical axis horizontally opposite said junctions of said output conduits with said side wall.
 6. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus having i. a housing having a fluid-dividing chamber therein, ii. a single input conduit feeding into said chamber, and iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis, B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and C. a conical member i. bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit, and ii. having the conical surface thereof disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall and intersecting said chamber outer wall to form the entirety of said chamber surface spanning said outer wall opposite said input conduit.
 7. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus having i. a housing having a fluid-dividing chamber therein, ii. a single input conduit feeding into said chamber, and iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis, B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and C. a conical member bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit and with the conical surface thereof being disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall, the length of said conical member along said vertical axis being coextensive within said chamber with the dimension along said axis of said junctions.
 8. Apparatus for dividing flowing fluid with precision into a number of portions of selected relative volumes, said apparatus having i. a housing having a fluid-dividing chamber therein, ii. a single input conduit feeding into said chamber, and iii. a plurality of output conduits feeding out from said chamber, and further having the improvement comprising A. a chamber outer wall of circular cross section in any horizontal plane passing therethrough with the centers of said circular cross sections being concentric along a common vertical axis, B. a separate junction along said outer wall for each said output conduit, with said output conduit junctions being centered on a common horizontal plane, and C. a conical member bounding said chamber wall opposite said input conduit with the apex of said conical member being directed along said vertical axis and toward said input conduit and with the conical surface thereof being disposed along said vertical axis at the location of said junctions of said output conduits with said outer wall, the length of said conical member along said vertical axis being equal to the dimension of said junctions along said axis. 